Relative economic values for Canadian beef production using specialized sire and dam lines

Abstract

A deterministic herd-level model was developed to simulate profit (income minus expense) from 100 beef cows in western Canada. The cow-herd was composed of three synthetic strains (M1, M2 and M4) mated in rotation and at equilibrium with respect to age and genotype. Two synthetic "terminal sire" strains (M3 and TX) were also simulated. Heifers were mated with M3 to minimize dystocia when calving at 2 yr of age. Cows greater than 5 yr of age were bred to TX. Baseline economic and biological data were obtained from Beefbooster breeders. Endpoints considered were weaned calves, backgrounded steer and heifer calves, finished steers and heifers, and carcass weight and grade. Variable costs included feed consumed by the cow-herd (76% of variable costs to weaning), non-feed items to weaning, and feed consumed by market progeny after weaning. Relative economic values (âi) were changes in profit ensuing from unit changes of the baseline strain specific biological characteristics. Elements of â were economic values for: cow weight, kg; male and female fertility, %; calf survival, %; direct and maternal effects on weaning weight, %; rates of gain on backgrounding and finishing rations, kg/d; feed conversion, dressing percent, % A grade and carcass cutability, %. For M1, M2 and M4 â was: [− 0.11 0.87 1.31 0.90 0.06 0.06 1.90 16.27 − 0.61 2.78 0.18 4.81]; for M3 â was: [0.00 0.38 0.00 0.28 0.03 0.00 0.95 4.74 − 0.21 0.92 0.06 1.67]; and for TX â was: [0.00 1.90 0.00 0.89 0.06 0.00 1.32 16.07 − 0.64 2.85 0.19 5.10] at the carcass endpoint. Direct and maternal weaning weight had greater âi at weaning than at later endpoints and âi for feed conversion increased in magnitude as time on feed increased. Key words: Beef cattle, selection program, breeding objective